Abstract
An automatic, on-line and real-time monitoring and estimation system (TOTOMES) for the cardiovascular dynamics under left ventricular assist device (LVAD) pumping has been developed to unload the operator who has to pay constant attention to the LVAD operation. The TOTOMES has the function which detects the presence and origin of accidents happening in the cardiovascular system, the pneumatic drive unit as well as the automatic controller. The parameters of the cardiovascular dynamics such as peripheral vessel resistance and arterial compliance are identified by using a time series model. The cardiac output of the natural heart is also estimated on the basis of the identified parameters. The inlet and outlet cannula resistances are calculated beat by beat on the basis of the principle of the optimal operating point. Detection of the malfunction is realized by using fuzzy logic. The combination of several measurements and estimates included in the antecedent of the fuzzy rules enables us to distinguish the origin of the malfunction. In in vivo experiment using an adult goat, it was ascertained that the proposed system successfully worked when the inlet cannula resistance was suddenly changed by clamping and when the blood withdrawing was carried out.
